"In Brazil, ultra-processed foods make up 25% to 30% of total calorie intake. We have McDonald's, Burger King and we eat a lot of chocolate and white bread. It's not very different, unfortunately, from many other Western countries," said coauthor Dr. Claudia Suemoto, an assistant professor in the division of geriatrics at the University of São Paulo Medical School.
"Fifty-eight percent of the calories consumed by United States citizens, 56.8% of the calories consumed by British citizens, and 48% of the calories consumed by Canadians come from ultra-processed foods," Suemoto said.
Ultra-processed foods are defined as "industrial formulations of food substances (oils, fats, sugars, starch, and protein isolates) that contain little or no whole foods and typically include flavorings, colorings, emulsifiers, and other cosmetic additives," according to the study.
"People who consumed more than 20% of daily calories from processed foods had a 28% faster decline in global cognition and a 25% faster decline in executive functioning compared to people who ate less than 20%," said study coauthor Natalia Gonçalves, a researcher in the department of pathology at the University of São Paulo Medical School.
For a person who eats 2,000 calories a day, 20% would equal 400 or more calories -- for comparison, a small order of fries and regular cheeseburger from McDonalds contains a total of 530 calories.
Those in the study who ate the most ultra-processed foods were "more likely to be younger, women, White, had higher education and income, and were more likely to have never smoked, and less likely to be current alcohol consumers," the study found.
"People need to know they should cook more and prepare their own food from scratch. I know. We say we don't have time but it really doesn't take that much time," Suemoto said.
"And it's worth it because you're going to protect your heart and guard your brain from dementia or Alzheimer's disease," she added. "That's the take-home message: Stop buying things that are super processed."